Here's the question you clicked on:
angelcui
find an equation in standard form having x-intercept -4 and parallel to the y-axis.
If it's parallel to the y axis then the graph is a constant x for any value of y |dw:1352065470358:dw|
but what is the equation? as in the Ax+By=C form?
It's just x=-4, because for whatever value of y, x is always equal to -4